This invention relates to a process for the selective production of para-diisopropylbenzene by catalytic propylation of cumene and/or benzene in the presence of a particular crystalline zeolite catalyst designated as ZSM-12.
Para-diisopropylbenzene has been used for a number of purposes, e.g., as solvents and chemical intermediates.
Alkylation of aromatic hydrocarbons utilizing crystalline zeolite catalysts has heretofore been described. U.S. Pat. No. 2,904,607 to Mattox refers to alkylation of aromatic hydrocarbons with an olefin in the presence of a crystalline metallic aluminosilicate having uniform pore openings of about 6 to 15 Angstrom unit. U.S. Pat. No. 3,251,897 to Wise describes alkylation of aromatic hydrocarbons in the presence of X- or Y-type crystalline zeolites, specifically such type zeolites wherein the cation is rare earth and/or hydrogen. U.S. Pat. No. 3,751,504 to keown et al and U.S. Pat. No. 3,751,506 to Burress describe vapor phase alkylation of aromatic hydrocarbons with olefins in the presence of a specified type of zeolite catalyst.
U.S. Pat. No. 3,755,483 to Burress discloses vapor phase alkylation of aromatic hydrocarbons in the presence of ZSM-12 zeolite catalyst. The reaction is carried out at temperatures between the critical temperature of the aromatic compound and 482.degree. C. (900.degree. F.). The critical temperature and pressure of benzene are 288.9.degree. C. (552.degree. F.) and 48.6 atm. (4.9.times.10.sup.6 N/M.sup.2).
Harper et al have described the catalytic alkylation of benzene with propylene over a crystalline zeolite (Petrochemical Preprints, American Chemical Society, Vol. 22, No. 3, p. 1084, 1977). Extensive kinetic and catalyst aging studies were conducted with a rare earth-exchanged Y-type zeolite (REY) catalyst.
U.S. Pat. No. 4,393,262 to Kaeding describes a process whereby benzene is brought in contact with ZSM-12 to selectively produce isopropylbenzene (i.e. cumene). This process may be carried out in the liquid or the vapor phase at temperatures of from about 100.degree. C. to about 300.degree. C. and pressure ranging from 10.sup.5 N/m.sup.2 to 6.times.10.sup.6 N/m.sup.2.
The entire disclosures of the above-identified U.S. patents are expressly incorporated herein by reference.